Utilities and other critical infrastructure users of the 6 gigahertz band have urged the FCC to protect incumbents from interference from unlicensed devices.
“The undersigned parties represent a broad cross-section of public safety providers and critical-infrastructure industries (CII) that use the 6 GHz band for mission-critical communications throughout the nation. This diverse group of organizations all share a common interest in preserving and protecting the 6 GHz band against interference to provide safe, secure, and reliable essential services to the public at large. Therefore, we join together in opposition to the Federal Communications Commission’s (Commission) Notice of Proposed Rulemaking regarding unlicensed use of the 6 GHz band,” the entities said in a filing Friday in ET docket 18-295 and GN docket 17-183. “Given the significant risk that the proposed unlicensed operations could have on mission-critical networks that are used to protect the safety of life, health and property, and provide essential services to individuals, businesses, governments and others across the nation, unlicensed operations should only be permitted in the 6 GHz band if the Commission adopts more stringent interference protections for co-channel and adjacent channel microwave systems, including proven technology to mitigate the risk of interference by prior coordination of unlicensed operations, as discussed below.
“We are very concerned that the proposed mitigation scheme for protecting public safety and CII users from interference—the Automated Frequency Coordination (AFC) system—is theoretical in nature and has not been tested or proven to work. Moreover, the Commission’s current proposal does not contemplate a mechanism for ensuring that unlicensed users take responsibility for the cost impact of the interference resulting from unlicensed devices operating in the 6 GHz band,” the filing added. “To mitigate the potential for interference to licensed microwave systems in the 6 GHz band, improvements are needed to the proposed AFC system. Given the significant risk that allowing unlicensed operations in the 6 GHz band could have on mission-critical communications networks, at the very least, the Commission should consider working with one or more federal laboratories to ensure that the untested interference mitigation measures proposed in the rulemaking will work before unlicensed operations are allowed in the 6 GHz band.
The filing said that the “vast majority” of the approximately 97,000 microwave links are licensed to public safety and CII parties, and it cited its use by public safety, railroads, utilities, and offshore oil and gas producers.
“There will likely be millions of unlicensed devices seeking access to the 6 GHz band, which will make protecting these public safety and CII networks from interference extremely difficult, if not impossible. Therefore, it is also important that the Commission adopt minimum standards for updating AFC systems and clarify that unlicensed operators or AFC system operators are legally liable for the consequences of interference to licensed microwave systems in the band,” the entities said. “This approach is necessary because CII have few, if any, options for relocating these systems should the Commission proceed as planned with this proposal. There is no currently available spectrum for relocation out of the 6 GHz band that provides the same capabilities, and while some of the entities we represent may consider using fiber, for many of our signatories below, deploying fiber across vast geographic territories is not economically or physically feasible. There are, on the other hand, numerous reasonable alternatives for unlicensed operations to use other bands.”
The filing was submitted by the American Gas Association, American Petroleum Institute, American Water Works Association, Association of American Railroads, American Public Power Association, Edison Electric Institute, International Association of Fire Chiefs, Government Wireless Technology & Communications Association, National Rural Electric Cooperative Association, Nuclear Energy Institute, and Utilities Technology Council, as well as 58 utility companies and other entities.
Separately, New York City said in a filing that it is skeptical of the conclusion of studies by unlicensed operation advocates that such devices can share the 6 GHz band without causing interference to public safety operations.
“Given the significant risk that the proposed unlicensed operations could pose to mission-critical networks – used to protect safety of life, health and property, and provide essential services to residents, visitors, businesses and government – the Commission must adopt more stringent interference protections, including for co-channel and adjacent channel operations,” the city said. “Technologies, once proven, can only be considered to mitigate the risk of interference by prior coordination of unlicensed operations. Not only are the proposed mitigation schemes for protecting public safety users from interferences theoretical in nature, the technologies are unproven, untested, and have not yet been built to mission critical standards.”
Meanwhile, an ex parte filing by CTIA reporting on meetings with FCC officials urged the agency “to use the opportunity at 6 GHz to enable both licensed and unlicensed uses to flourish by providing a better balance between licensed and unlicensed spectrum. Specifically, participants asked the Commission to promptly issue a Further Notice of Proposed Rulemaking to repurpose the upper portion of the 6 GHz band for exclusive use, flexible rights licensing, consistent with CTIA’s advocacy in the proceeding.”
The filing added that a further notice “need not delay Commission action on unlicensed operations in the lower portion—subject to rigorous interference protection. To that end, participants expressed support for unlicensed in a portion of the 6 GHz band, so long as a positive control interference protection framework is adopted for all unlicensed devices, including low-power indoor and very low power indoor/outdoor devices. Positive control via Automatic Frequency Coordination (‘AFC’) is necessary both to prevent interference and to resolve interference when it does occur, regardless of unlicensed device location or power level. As the attached presentation shows, recent RLAN technical filings contain unreasonable assumptions, unsuitable methodologies, and unsupported conclusions. In short, RLAN [radio local area network] stakeholders have not shown that low power indoor devices or very low power indoor/outdoor devices can operate without causing harmful interference to incumbent 6 GHz licensed operations absent AFC control.”
In another filing, the National Association of Broadcasters said that it “does not oppose the consideration of unlicensed operations in portions of the 6 GHz band. With appropriate safeguards, including frequency coordination, NAB believes that unlicensed operations can co-exist with certain fixed wireless uses. However, the WiFi uses under consideration in this proceeding are fundamentally incompatible with mobile broadcast operations used for electronic newsgathering. Electronic newsgathering operations, unlike fixed uses, are itinerant and not subject to coordination. Further, the solutions proposed to protect electronic newsgathering and other mobile uses of 6 GHz spectrum, including public safety operations, will be entirely ineffective. Restricting unlicensed operations to indoor use will fail to protect mobile users for at least two reasons. First, electronic newsgathering itself frequently takes place indoors and at similar power levels to WiFi. Second, there is no reason to believe that WiFi signals from indoor access points and devices will in fact remain indoors. For these reasons, the Commission should not allow unlicensed operations in those portions of the 6 GHz band allocated for mobile use.”
In a filing by NCTA reporting on a meeting with FCC staffers, the trade group said it “and its member companies expressed support for authorizing unlicensed use of the full 1200 megahertz of 6 GHz spectrum provided that existing incumbent operations can be fully protected. In particular, we urged the Commission to move forward in the near term with authorizing low-power, indoor (LPI) use throughout all 6 GHz sub-bands without requiring Automated Frequency Coordination (AFC). LPI use presents the least risk of harmful interference to incumbents due to building attenuation, as the technical studies on the record demonstrate. Unlicensed LPI operations across all 1200 MHz of the band would also be an incredibly powerful tool to relieve congestion in existing Wi-Fi bands, support 5G deployment by providing much-needed capacity, and bring Wi-Fi 6 equipment to consumers.”
NCTA added that it “also encouraged the Commission to adopt additional measures to ensure that LPI devices protect incumbents from harmful interference. First, to ensure that indoor devices stay indoors, NCTA supported the following methods: (1) prohibiting the use of removable antennas; (2) requiring that devices must be plugged in; (3) requiring that devices cannot be weatherproofed; and (4) requiring that such devices be labeled ‘indoor only.’ We also reiterated our view that the equipment authorization process may serve as a good vehicle to enforce an indoor-only restriction. Second, we opined that the Commission can help to facilitate coexistence in U-NII-6 and U-NII-8 among indoor mobile/portable BAS and wireless microphone operations and LPI unlicensed devices by requiring that LPI deployments at stadiums, conference centers, and other large event venues be subject to coordination with the designated frequency coordinator for the venue.” —Paul Kirby, [email protected]
MainStory: FCC FederalNews SpectrumAllocation PublicSafety
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